Electron discharge device control system



Feb, 13,940. l. K. DORTORT 2,139,732

ELECTRON DISCHARGE DEVICE CONTROL SYSTEM Filed Peb. 5, 1934 '7Sheets-Sheet l Feb. 13, 1940. f I. K. 'QRTORT 2,189,782

ELECTRON DISCHARGE DEVICE CONTRdL SYSTEM Filed Feb. 5, 1934 7Sheets-Sheet 2 Feb. 13, 1940. K. DORTORT 3 ELECTRON DISCHARGE DEVICECONTROL SYSTEM Filed Feb. 5. 1934 7 Sheets-Sheet 3 Feb. 13, 1940. I. K.DORTORT 2,139,782

- ELECTRON DISCHARGE DEVICE CONTROL SYSTEM Filed Feb. 5, 1934 7Sheets-Sheet 4 A l A A A A AA 2; 69

m fl m I. K. DORTORT ELECTRON DISCHARGE DEVICE CONTROL SYSTEM Feb. 13,1940.

7 Sheets-Sheet 5 I IIIIMH' J 37 Filed Feb. 5, 1934 Feb. 13, 1940; I. K.DORTORT ELECTRON DISCHARGE DEVICE CONTROL SYSTEM Filed Feb. 5, 19:54 7Sheets-Sheet s Feb. 13, 1940. K. DORTOR T ELECTRON DISCHARGE DEVICECONTROL SYSTEM Filed Feb. 5, 1934 7 Sheets-Sheet 7 n1 5 g a 8 .HH gm.mm1 .5 MN 2| g2. i5.

Patented Feb. 13, 1940 UNITED STATES PATENT OFFICE SYSTE Isadore K.Dortort, Milwaukee, Wis., assignor to Allis-Chalmers ManufacturingCompany, Milwaukee, Wis., a corporation of Delaware Application February5, 1.934, Serial No. 709,820

21 Claims.

This invention relates'in general to improvements in electron dischargedevice control systems and more particularly to means for energizing thecontrol electrodes of an electric valve to control the flow of currenttherethrough in a more accurate and efiicient manner than was possibleheretofore.

' Electric valves are frequently utilized for controlling the flow ofcurrent through circuits associated therewith to thereby constitutesystems such as alternating current rectifying, direct currentinverting, frequency changing and other systerns. In general, the flowof current through each anode of the valve is to be releasedperiodically by suitable means such as control electrodes, the how ofcurrent being prevented by maintaining the control electrode at apotential below the so-called critical potential which is approximatelythe same as the potential of the cathode, and is released by bringingthe control electrode to a potential higher than the criticial potentialor cathode potential. In valves of the vapor type, the value of thecritical potential depends on the operating conditions within the valveso that, when the control electrode potential varies in a gradualmanner, the release of the flow of ourrent'occurs at intervals which arenot accurately defined. It is, therefore, desirableto impress, on thecontrol electrode, a potential suddenly passing from a finite negativevalue to a finite positive value to thereby release the flow of currentat precise intervals even when the critical potential does not remainconstant. Conversely, if a control electrode is used of the type wherebythe flow of current may be suddenly interrupted by deionization of thearc path, the control electrode potential should preferably passsuddenly from a positive value to a negative value. In valves of thevacuum type, the impedance of the valve varies with the potential of thecontrol electrode and it is then advantageous to vary such potentialsuddenly between a negative value sufiicient to prevent the flow ofcurrent and a positive value sufiicient to cause the valve to oppose aminimum impedance to the flow of current therethroughand thus obtainsuch flow of current at the highest possible efficiency. Controlpotentials having such characteristics may be conveniently obtained bymeans of circuits supplied with alternating current and supplyingcurrent to inductive devices through controllable auxiliary electricvalves. The connections between the auxiliary circuits and the controlelectrodes may be-rnade in several different ways as will appearhereinafter. F

1 It, is, therefore, among the objects of the present invention toprovide a control system for an electron discharge device in which thecontrol electrodes of the device are energized through circuitscomprising auxiliary electron discharge devices.

Another object of the present invention is to provide a control systemfor an electron discharge device in which the control electrodes of thedevice receive potentials of which the polarity is suddenly reversed atrecurring intervals.

Another object of the present invention is to provide a control systemfor an electron discharge device in which the control electrodes of thedevice receive potentials from circuits containing inductive devices andwhich are controlled by means of auxiliary electron discharge devices.

Another object of the present invention is to provide a control systemfor an electron discharge device in which the control electrodes of thedevice receive potentials which are regulated in relation with operativeconditions of the system.

Another object of the present invention is to provide a control systemfor an electron discharge device in which the control electrodes of thedevice receive potentials including a negative potential impressedthereon upon occurrence of a disturbance in the system.

Objects and advantages, other than those above described, will beapparent from the following description when read in connection with theaccompanying drawings, in which:

Fig. l diagrammatically illustrates one embodiinent of the presentinvention applied to the con trol of an electric valve utilized in asystem for rectifying alternating current and in which the controlpotentials are regulated in relation with the power output of the valve;

Fig. 2 is a diagram of the wave form of some of the voltages appearingin the circuits of the embodiment illustrated in Fig. 1;

Fig; 3 diagrammatically illustrates a portion of a modified embodimentof the present invention modified embodiment of the present inventiondiffering from the previously illustrated embodiments in that thecontrol electrodes. of the valve receive potentials having a frequencydouble. the frequency of the potentials impressed on the associatedanodes, such potentials beingregulated in relation with the intensity ofthe flow of current through the valve;

Fig. 8 is a diagram of the wave form of some of the potentials appearingin the circuits of the embodiment illustrated in Fig. 'lj

Fig. 9 diagrammatically illustrates the application of the control.electrode energizing circuits illustrated in Fig. 'l to the control ofan elec tric valve regulating the fiow of current through the windingsof an electric motor and in which the control potentials are regulatedin relation with the speed of such motor;

Fig. 10 diagrammatically illustrates a modification of the speedresponsive elements ofthe em bodiment illustrated in Fig. 9; and

Fig. 11 diagrammatically illustrates a portion of the regulatingcircuits differing from the circuits illustrated in Fig. 9 in that thecontrol potentials are regulated thereby in function of the power outputof the motor.

Referring more particularly to the drawings by characters of reference,reference numeral I 6 designates an alternating current supply lineherein represented as a three-phase line operating at any suitablevoltage having any suitable frequency. It is assumed that it is desiredto convert alternating current from line it into direct current to besupplied to a direct current line having a negative conductor l7 and apositive conductor it. Line I6 is accordingly connected with the primarywinding 2! of a transformer is having a secondary winding 22 arranged inany suitable manner and provided for examplewith a plurality of phasedisplaced portions connected in star to form a neutral point connectedwith conductor IT. The different phase portions of winding 22 areseverally connected with the anodes such as 23 of an electric valve 241of any suitable type. The preferred form of valve illustrated in thepresent and following embodiments is the type in which the current isconducted through mercury vapor produced at a cathode 28 connected withconductor 18. It will be understood that valve 24 is provided with theusual discharge ignition and maintaining means which are well known andtherefore not shown. As is usual the potential of the cathode 23 will betaken as datum for the potentials impressed on the discharge controlmeans consisting of control electrodes such as be taken as datum for thepotentials impressed on the associated control electrodes.

The control electrodes of the valve receive periodic potentials from thesystem to be described immediately hereafter. Such system comprises atransformer 28 energized from line l6 and having a secondary windingdelivering voltages similar to the voltages of line it and of winding22. Such secondary winding comprises a plurality of phase displacedportions connected in star in the embodiment illustrated in Fig. l andseverally supplying current to a plurality of independently functioningcontrol circuits each comprising a resistor as at 29 in series with areactor as at 3! and an auxiliary electric valve as at 32. The auxiliaryvalves are of any suitable type but it is preferred to utilize valves ofthe type in which the discharge is conducted through a gas or vapor andof which the action is controlled by means of a control electrode as at39.

The control electrodes of the auxiliary valves are severallyconnected'with the secondary windingt l of a transformerilt energizedfrom line is.

to receive therefrom phase displaced alternating potential componentssuperimposed on a common unidirectional potential component appearing ina circuit connecting the neutral point of winding 33 with the cathodesof the auxiliary valves. Each reactor 38 is connected in parallel withthe primary winding of a transformer as at 33 having a secondary windingconnected between conductor [8 and one of the control electrodes as atEl of the main valve; if so desired transformer 35 may, be omit ed andreplaced by a secondary'vvinding arranged on the core'of reactor 3l. Itwill be understood that a source of constant uni-directional potentialsuch as a battery 3"! may be inserted in the common connection of themain'control electrodes with con.- ductor it although such battery willbe considered as being omitted in describing the operation of thesystem. It will also be understood that the circuits of thecontrol'electrodes of the main and auxiliary valves may comprisesuitable impedance meansfor limiting the flow of current therethrough asis usual in the art.

The connection between the neutral point of winding 35 and the cathodesof the auxiliary valves may comprise a source of either constant orvariable uni-directional potential, such potential varying in relationwith the power output of valve 2-". in-the present embodiment. To obtainsuch variation a current transformer 38 is inserted in one of theconnections between winding 2! and line it, such current transformerhaving a secondary winding provided with a midtap and supplyingcurrentto a resistor 39. Such secondary winding is also connected withthe anodes of a pair of auxiliary valves 4| which are preferably of thehigh vacuum type in which the flow of current is continuously regulatedin function of the anode and control electrode potentials. The cathodesof valves Al and also of the set of valves such as 552 are connectedwith a tap of a voltage divider 2 connected across lines 11,. I8; andthe control electrodes of valves 4! are jointly connected withconductor. H3 through a. suitable bias battery id and the resistor 42.The midtap of the secondarywinding of current transformer 381'sconnected with the neutral point of winding 34. To obtain ,asubstantially uniform potential between theneutral point of winding 34,and the cathode of the auxiliary valves, suitable filtering means mayb-e provided such as a reactor 43 curve 46 represents the voltageimpressed on anode'23 as a result of energization of transformer l9 fromline 16. Assuming that the fiow of current through valve 24 has not yetbeen established, current transformer 38'receives no appreciable amountof current and the neutral point of winding 3 is accordingly at thepotential of the cathodes of valves ii and 32. The connections oftransformer 28 with line I6 and with the auxiliary valves are such thatthe anodes of the valves 32 receives therefrom a potential which may berepresented by curve 47 which is similar to curve 45 and is in suitablephase relation therewith. Control electrode 39 then receives, fromwinding 36, an alternating potential which is preferably in phasecoincidence with the potential of the associated anode and may,therefore, be represented by curve 49 becoming positive at an instantrepresented by point A of the time abscissa. Valve 32 accordinglybecomes conductive at time A and carries current during the timeinterval A, B of positive energization of the anode and during a furtherinterval BD as a result of the presence of reactor 3! in the circuitthereof. Resistor 29 and reactor 3| are so proportioned as to causereactor 3! to absorb the greater part of the voltage impressed on thecircuit thereof; the voltage drop across reactor 3| then followssubstantially curve AFBEDC, such potential suddenly decreasing to zeroat time D at which the current tends to reverse but such reversal isprevented by the valve action of valve 32. A voltage or" similar waveshape is impressed on control electrode N by transformer 36, suchvoltage becoming positive while anode 23 is positive and releasing theflow of current through such anode. Such flow of current continues untilanode 23 becomes negatively energized from winding 22 or when the flowof current is released through another anode at higher potential. Suchsequence of operation is repeated for each anode of valve 2 to cause theflow therethrough of a substantially uniform current.

As a result of such flow of current, current transformer 38 impresses onresistor 39 and on the anodes of valve iii potentials proportional tothe intensity of such current and therefore also proportional to theintensity of the flow of current through valve 24 and line H, l8. Suchpotentials cause a flow of uni-directional current through valves ii,such flow of current being modified by the action of the controlelectrodes of such valves which are energized from voltage divider 4'2at a positive potential in relation with the magnitude of the voltage ofline I1, H3. The uni-directional output voltage of valves 4! impressedbetween the neutral point of winding 3% and the cathodes of the valvessuch as 32 therefore varies in relation with the intensity of the flowof current through line ll, l8 times the voltage of such line, andtherefore in relation with the power output of the valve 25. Suchvoltage may be represented by a straight line 48 intersecting curve 49at a time G- at which control electrode becomes positive to release theflow of current through valve 32. Such flow of current continues duringinterval GB and continues during a further interval BH which is,however, shorter than interval BD. If the voltage drop in the dischargethrough valve 32 is considered as negligible, the voltage appearing atthe terminals of reactor *i will follow the dissymmetrical heavy linecurve derived from curve 41. Such voltage is impressed on transformer 36of which the secondary voltage is then represented by curve 5| which isidentical to the heavy line curve above mentioned but which is displacedwith respect to the axis of abscissas by an amount such that the averagevalue of such voltage over a complete cycle be zero, as auni-directional component of voltage cannot be transmitted through atransformer. It will be noted that at time G the voltage represented bycurve 5i suddenly passes from a negative value to a positive value,thereby causing a positive release of the flow of current through anode28 at time G irrespectively of the operating conditions within the valve24. Such sequence of operation is repeated successively for every anodeand control electrode of valve 24 to cause the output voltage of valve24 to follow curve 52 comprising portions of the several voltage curvesof the anodes of the valve.

If so desired, the voltage impressed on line H, l8 may be renderedsubstantially uniform by providing suitable filtering means in thecircuits as is well known in the art. If the load of line IT, I8increases the potential impressed by cur-- rent transformer 38 andvalves on the neutral point of winding 34 increases to an extentcommensurate with such increase of load, causing the auxiliary valvessuch as 32 tobecome conductive at a later instant of the voltage cyclethereof, whereby the control potential impressed on the controlelectrodes of the valve M become positive at a later instant and theaverage output voltage of valve 24 decreases. If the load of line l1, [8decreases, the output voltage of valve 24 is caused to increase by theoppos te process. The system accordingly causes the flow of energythrough transformer l9 and valve to be maintained at a substantiallyuniform value, although it will be understood that the circuits may alsobe adjusted to regulate such flow of energy only when such flow exceedsa predetermined value to cause such flow of energy to be limited in itsmagnitude, and to be unregulated when it remains below the limitingvalue.

In the present system, therefore, transformer I9 and the valve Mconstitute electric translation means connected with supply line it andcomprising an alternating current winding and also an electric valve 24having anodes 23, control electrodes 21 and a cathodeili. Line iiiimpresses an electromotive force similar to an electromotive force ofwinding 22?. on a control circuit comprising resistor is, reactor 31 andauxiliary valve 32 to thereby generate a periodic potential impressed ona load circuit constituted by the connection of control electrode Elwith cathode 26. Transformer 36 impresses, on such load circuit, apotential component similar to a component of the potential across aportion of the control circuit, such portion being reactor 3 1. Valve 32controls the flow of current through the circuit in such a manner as toimpress on control electrode 21, potentials of signs and magnitudesoperative to control the flow of cur..ei:i.t through valve 24. Valve 32is provided with discharge controlling means such as control electrode30 cyclically controlling the operation the valve as a result of theconnection thereof with energizing means operating in relation with thevoltage cycle of line i6. Such energizing means impress, on controlelectrode potentials of signs and magnitudes operative to cause valve'32 to be alternately conductive and non-ccnductive at recurringintervals in relation with voltage cycle of line l6 and winding 22. Forregulating the action of .suchenergizing means, the

tion with such current.

control potentials comprise a uni-directional component in relation withthe magnitude. of a component of the flow of current in line Hi and alsoin relation with the magnitude of the flow of energy between line l6 andline H, l8. Such component results from an alternating potential inrelation with the intensity of the flowof current through valve 24obtained from current transformer 38 and rectified and regulated byvalves 4|.

In the embodiment illustrated in Fig. 3, the alternating potentialimpressed by current transformer 38 on winding 34 through valves 4! isregulated through the valve in response to the intensity of only theflow of current through valve 24. To obtain such result, the controlelectrodes of valves 4| receive a direct current potential in relationwith the intensity of the flow of current through conductor ll from ashunt 53 inserted therein, the average output voltage of valves 4! thenvarying in relation with the square of the current through valve 24 asthe currents flowing through current transformer 38 and through shunt 53are both in direct propor- When such flow of current increases, theaverage output voltage of valve 24 is accordingly caused to decrease andconversely when the flow of current decreases, the output voltage ofvalve 24 increases with the result that the flow of current is regulatedat a substantially uniform value. The circuits may, however, also beadjusted to limit the flow of current to a predetermined value and toleave such flow of current unregulated when such value is not reachedthereby. It will be understood that the action of shunt 53 on valves 4|may be magnified by insertion of suitable voltage amplifying means inthe connections therebetween or by providing valves 6! with screen gridsas is well known in the art.

In the embodiment illustrated in Fig. 4 the connections of the severalwindings of transformer 28 are assumed to be such as to cause thepotentials represented by curves ll and 46 to be in the phase relationas illustrated in the diagram of Fig. 5. In the present embodiment, eachtransformer as at is connected between the anode and the cathode of theassociated valve to impress on the associated control electrode asat 21potentials opposite in sign to those appearing across the valve". Thedirect current voltage component impressed on each control electrode asat 38 through winding 34 is made to vary in relation with the componentof the flow of current through line 18 which is not utilized forenergizing line H, i8. Assuming that line I6 is supplied from a singlegenerator 66, a potential in relation with such current component may beobtained by means of a current transformer 61 inserted in line 16between the connection of transformer l9 therewith and the outgoingportion of the line. The secondary winding of current transformer 6'! isutilized for impressing a uni-directional potential between the cathodesof the auxiliary valves as at 32 and the neutral point of winding 34 ina manner similar to that illustrated in Fig. l, the control electrodesof valves 4! receiving, however, alternating potentials obtained from apotential transformer 68 connected with line it through a suitableimpedance device 69' to obtain the desired phase relation between theanode and control electrode potentials of valves M. In the presentembodiment, the cathodes of all valves are connected with conductor l8.The connectionsof the control electrodes of valve 24 includes a resistor69 connected between cathode 26 and battery 31. Such resistor isconnected to receive current from one or more current transformers llinserted in the connection between winding 2! andline I6, such currentbeing rectified by means of a rectifier device M to thereby cause theappearance of a substantially uniform negative voltage across theterminals of resistor 69. Each current transformer H is bridged by acircuit comprising a reactor '12 and a capacitor 13 constituting anon-linearly resonant element having-a low reactance while the flow ofcurrent through the associated current transformer ll is less than apredetermined permissible value and having a high reactance when suchflow of current exceeds the permissible value.

If the voltage drop of the discharge within valve 32'be again neglectedit will be seen that the voltage between the anode and the cathode ofvalve 32 and impressed on the primary winding of transformer 36 may berepresented by the portions of curve 41 not drawn in heavy line in Fig.2, such portions being drawn in heavy line in Fig. 5. The voltageappearing across the terminals of the secondary winding of transformer.36 then follows a curve It which is similar to the heavy line curveabove mentioned reversed in polarity and drawn with respect to an axisof abscissas so chosen thatthe average voltage over a complete cycle iszero. The voltage represented by curve It passes suddenly from anegative to a positive value to release the how of current through anode23 in a positive and accurate manner, thefiow of current occurringsimilarly through the several anodes to cause the,

output voltage of valve 24 to again follow curve 52. In the presentembodiment, if the average output voltage of valves 4! represented byline 48 increases, the release of the flow of current through valve 32is again retarded but the instant at which suchflow of current ceasesoccurs at an earlier time, The flow of current through anode 23 istherefore released at an earlier instant and the average output voltageof valve 24 is increased. Conversely, when the average voltage of valves4| decreases, the average output voltage of valve 24 decreases tomaintain such output voltage in predetermined relation with the currentthrough transformer 5! and the voltage impressed on transformer 68.

During normal operation of valve 24 the flow of current remains below apredetermined value in relation with the rated value of the valve andreactor 72 and capacitors T3 are then in reschance for the frequency ofthe voltage impressed thereon by current transformer H, such frequencybeing that of the voltage in line I 5. Each current transformer H istherefore substantially short circuited by the reactor and capacitor connected therewith so that the potential impressed thereby on resistor 69is at a negligible value. Upon occurrence of a disturbance causing theflow of current through transformer 59 to reach an excessive value, oneor more of the current transformers H impress, on the associated reactorl2 and capacitor 73, an alternating voltage of such magnitude as tocause the reactance of the reactor to vary and thereby to cause thereactor and the capacitor to be no longer in resonance. The

' potential of the secondary winding of the current transformer istherefore impressed at substantially the full value thereof on resistor69 through rectifiers M to cause a negative potential toube former 38connects the load circuit, comprised by the control electrode ZIandcathode 26, across valve 32 to impress on control electrode 21 apotential'component similar to a component of the potential between theanode and the cathode of valve 32. The energizing means for controlelectrode 38 are regulated by the action of the uni-directionalpotential of valves 4| which is in relation with the magnitude of acomponent of the flow of current in line It and also in rela-- tion withthe power factor of such flow of current due to thecontrol of valves 4|by means of transformer 88. Current transformers H constitute means forobtaining an alternating potential in relation with the intensity of theflow of current through transformer I9 and valve 24, rectifiers 14converting such potential into unidirectional control potentialimpressed on control electrode 21 'by means of resistor 89. Reactor l2and capacitor 13 constitute non-linearly resonant impedance meanscontrolling the relation between such uni-directionalpotential and theintensity of the flow of current through valve 24.

In the embodiment illustrated in Fig. 6, the anodes of valves 4|are'energized from transformer' 68whereas the control electrodes of thevalves are energize'd from transformer 6i. In general the voltages ofline l6 may be assumed to be of constant value so that the averageoutput voltage of valves 4| will be equal to a substantially constantvalue'modified by the action of the control electrodes in accordancewith the power factor of the current flowing through current transformer61. The output voltage of valve 24 will accordingly beregulated to varyin relation with such factor to causethe power factor of thetotal'current supplied by generator 66 to be regulated'in the desiredmanner.

In the embodiment illustrated in Fig. 7 the secondary winding portionsof transformer 28 are connected to form three single phase windingshaving separate neutral points. Each winding thus formed is connectedwith the anodes of a pair of valves as at 32 and whereby each reactor asat 3| and each resistor as 29 receives substantially uniform rectifiedcurrent, the reactors and resistors then being equal in number toonehalf of the number of valves. Transformer 36 is then again connectedacross reactor 3| to supply control potential to control electrodes 21and 18 associated with anodes 23 and 19 receiving potentials in phaseopposition from winding 22.

In the present embodiment the uni-directional potential impressedbetween the cathodes of the valves and the neutral point of winding 34is :made to vary in relation with the intensity of the flow ofcurrent-through transformer l9, such potential being obtained fromcurrent transformer 38 in a manner similar to that illustrated in Fig. 3or by reotifying the secondary voltage of transformer 38by means of abridge rectifier 88 and impressing the rectified voltage on the voltagedivider 83. The relation between the uni-directional potential thusobtained and the intensity of the flow of current through transformer I9is controlled by means of a' reactor 8| and a capacitor 82 constitutinga non-linearly resonant element having a high impedance when the flow ofcurrent through transformer i8 is below the value desired therefor and alow impedance when .gsuch flow of current is greater than the valuedesired therefor, such impedance varying rapidly when the currentdeparts from the desired value by a small amount. The cathodes of thevalves 32, -11, etc., are normally connected with transformer 28 throughthe reactors as at 3| and through contacts of a relay 84 energized froma current transformer 86 inserted in the connection between transformerl9 and line it. Such relay is so adjusted as to operate upon flow ofexcessive current through transformer 3 to then connect each reactorwith the associated control electrodes of valve 24 instead of withthecathodes of the associated auxiliary valves.

In the diagram of Fig. 8 the potential impressed on the anode of valve11 is represented by curve 86 similar to curve 41 but displacedtherefrom by 180. The potential of control electrode 85 of valve 1'! maythen be represented by curve 81 displaced with respect to curve 49 byindicating that-control electrode 85 becomes positive at a timerepresented by point L to thereby release the flow of current throughvalve 11. The combined output voltage of valves 32 and '11 may bederived from curves 41 and 86 as shown in the heavy line drawn in Fig.8,'such voltage being impressed, to itsgreatest extent, on reactor 3|,the reactance of which is assumed to be sufiicient to cause the flow ofuni-directional current therethrough to be uninterrupted. Controlelectrodes 21 and 18 will then receive a common potential represented bycurve 88 similar to the heavy line curve above mentioned but displacedwith respect to the axis of abscissas so as to render the averagevoltage thereof over a complete cycle equal to zero. Such energizationof the control electrodes causes the flow of current through anode 23 tobe released at time G as in the embodiment illustrated in Fig. 1 and theflow of current throughanode 19 to be released at time L at a voltagerepresented by curve 89. The flow of current through the remaining pairsof anodes of valve 24 is released in a similar manner to cause the flowof current to occur therethrough at a voltage represented by curve 52.

From a consideration of Fig. 8 it appears that during interval KL anode19 becomes increasingly positive with respect to cathode 26, thevoltages of the anode and cathode being represented by curve 89 and acurve substantially identical with curve 52 respectively. During suchinterval anode 19 has an increasing tendency to carry current which mustbe overcome by the action of the control electrode 18 until the flow ofcurrent is released at time L. During interval KL control electrode 18becomes increasingly negative, the potential thereof being representedby curve 88 and therefore effectively opposes the tendency of anode 19to carry current prematurely with the use of a potential of minimumamplitude.

When the flow of current through transformer l9 increases or decreases,the output voltage of current transformer 38 and rectifier 88 increasesor decreases to agreater extent controlled by reactor 8| and capacitor82 to cause the output voltage of valve 24 to decrease or to increaseand thus maintain the flow of current through valve 24 at substantiallya predetermined value or to limit such flow of current to the desiredvalue. Upon occurrence of a disturbance causing the flow of excessivecurrent through current transformer 86, relay 84 energized thereby iscaused to operate to disconnect the several reactors from the cathodesof the valves and to connect each reactor with the associated controlelectrodes. As a result of such operation control electrodes 21 and 18receive, from valves 32 and 11, a negative potential through a circuitincluding control electrodes23 and it, a contact of relay 84, reactor3|, resistor 29, transformer 28, valves 32 and 11, to conductor 18. Flowof current also occurs from conductor l8 through battery 31, transformer36, a contact of relay 94, reactor 3 I, resistor 29, transformer 28 andvalves 32 and'l'i, the flow of such current through reactor 3 l causingthe uni-directional potential impressed on the control electrodes by thevalves to, bemaintained at a substantially uniform value operative tocause the flow of current through the associated anodes to cease.- Theremaining control electrodes of valves Ztbeing' similarly energized, theflow of current through the valve ceases and the normal operation can beresumed. 1

Line it, accordingly, operates as a source of current for the pair ofvalves 32 and 1'! which are operatively connected to supplyuni-directional current therefrom to reactor 3| and cooperates withcurrent transformer 38, rectifier Bil and transformer 33 to impress, 0nthe control electrodes of the valves, recurring potentials of signs andmagnitudes operative to cause each of such valves to be alternatelyconductive and non-conductive in sequence (with respect to the other,valve)" in relation withthe voltage cycle of line Such controlpotentials include a uni-directional potential component in relationwith the intensity with the flow of current through transformer l9 andvalve 24, the relation between such potential and the intensity of suchcurrent being controlled'by the nonlinearly resonantimpedance means 8|and 82.

Relay" 34 operates in response to abnormal conditions in the system forconnecting the valves 3'2 and 'E'F with control electrodes .23 and '18to constantly impress negative potential thereon.

In the embodiment illustrated in Fig. 9, line Hi suppliescurrent to thewindings of a motor 93 through a single phase transformer 92 having asecondary winding provided with a midtap, the flow of such current beingcontrolled by an electric valve QB similar to valve 24 but provided withanodes different in number from the number of anodes of valve 24. Line.l1, I8 is con nectedbetWeen the midtap of transformer 92 and thecath'ode of valve 9! to supply current through the field winding 94 ofthe motor. The armature windings 96 of the motor are severally connectedbetween transformer 92 and the anodes such as Etand E9 of valve 9I.--The control electrodes such as 2'! and 78 of the valve are generallymaintained negative by means of a suit,

able source such as a pair of rectifying devices 9? converting currentreceived from line H5. The flow of current through the particulararmature windings Q6, operative to cause "a torque to be impressed onthe shaft of the motor, is controlled cy means of a distributor having abrush operating in relation with the movement of shaft of the motor andsupplying, to the control electrodes, control potentials obtained fromvalves 32 and 77 in a manner similar to that illustrated in Fig. 7. Theanodes of valves 32 and; ll are connected with a transformer 99 andcontrol electrodes 38 and 85 are connected with a transformer i i suchtransformersbeing ener-- gized from line Eli. Theuniedirectionalpotential component impressedon control electrodes 30 and 235 issupplied from a direct current generator l driven from shaft 95 andtherefore delivering current at a voltage in relation with the speed ofthe motor.

In the position shown the distributor is without efiect on the action ofthe control electrodes of valve 9i with the exception of controlelectrodes 2? and 8 and the flow of-current through all anodes exceptanodes 23 and I9 is therefore precluded as a result of the negativeenergizati'on of the associated control electrodes. Control electrodesZl' and 18 receive, through distributor 96, a periodic potential topermit the alternate flcwof current through anodes 23 and 19. Suchcurrents combine in valve 9| to cause the flow of substantially uniformdirect current through conductor 18, field winding 94, conductor I! backto transformer 92, causing a torque to be-impressed on the shaft of themotor resulting in rotation of said shaft in a predetermined direction.After a material length of time which may amount to several cycles ofthe voltage of line IE3, the brush of the distributor 98 engages withanother segment of the distributor, therebyoausing the flow ofcurrent-through anodes 23 and "19 to cease and causing the flow ofcurrent to be released through another pair of anodes. Such sequence ofoperation is repeated for every pair of anodes and armatiu'e windings tocause the flow of substantially uniform current through the motor andthe continued rotation of the shaft in a uniform direction. If the speedof the motor increases, the output voltage of generator B02 increases,causing valves 32 and 11 to carry current at a later portion of thevoltage cycle of line It and thereby causing the average output voltageimpressed on windings 96 and 7 valve 9! to decrease. Conversely", whenthe speed of the motor decreases, the output voltage of valve 9iincreases to thereby maintain the speed of the motor at a substantiallyuniform value.

Such value may be regulated by means of a rheostat i 05 inserted in thefield circuit of generator. I02. Such generator therefore constitutesmeans for obtaining a uni-directional potentialcomponent in relationwith the speed of the. motor and which component isto beimpressed oncon- ,trol electrodes 30 and 85 of. the auxiliary valves.

In the modified embodiment partially illustrated in Fig. 10, alternatingcurrent generator I03 is substituted for generator [02, the outputvoltage of generator l03'being converted into a uni-directional voltagecomponent by means of a bridge rectifier m4. For a particular adjustmentof rheostat I05, the output voltage ofgenerator I03 is proportional tothe speed of the .motor and the uni-directional voltage obtainedtherefrom controls the operation of the motor in the same manner as wasdone, by means of generator I02 in the embodiment illustrated in Fig."

9. The relation between such voltage and the speed of the motor may bevaried by means of rheostat 05 and also by insertion across theterminals of generator I03 of acapacitor I01 and of a reactor I06 acrosswhich rectifier I04 is connected; The reactor and the capacitor conmotorvaries, the magnitude of the voltage of generator M3 as well as thefrequency thereof varies and such frequency value may be suificient tocause variation of the resonant frequencyof reactor Hill withcapacitator I01, and the variations of 1e magnitude of such Voltage maytherefor be utilized instead of the variations of the frequency forcontrolling the speed of the motor.

In the embodiment illustrated in Fig. 11, the field winding oi generatorIE2 is excited in function of the flow of current through trans-former 2cy means-of a current transformer ml and a bridge rectifier Kid. Theoutput voltage of generator [t2 then becomes proportional to the speedof the motor as a result of the operation of the armature thereof fromshaft 2'35 and also proportional to the intensity oi the flow of currentthrough the motor which in turn is propor tional to the torque of themotor. Such voltage is therefore proportional to the torque times thespeed of the motor or to the output energy of the motor andmaintainssuch energy at a substantially uniform value.

Although but a few embodiments of the present invention have beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

3 It is claimed and desired to secure by Letters Patent:

l. The combination with an alternating current supply circuit, anelectric current work circuit, and electric valve means interconnectingslid circuits comprising an anode and a cathode constituting spacedelectrodes for the flow oi current therebetween, of means forcontrolling said flow of current comprising a control electrodeconstituting an element of said valve means, and means for producing andimpressing on said contro]. electrode potential impulses ofsubstantially perpendicular wave front comprising a control circuithaving included therein a reactor and an auxiliary electric valveconnected toreceive an electromotive force similar to the electro--motive of said supply circuit, discharge controlling means connectedfor cyclically controlling the operation of said auxiliary valve tothereby control the flow of current through said reactor,

and means coupling said reactor with said con- I11 trol electrode toimpress on the latter potential component similar to a component of thepotential across said reactor.

The combination with an alternating current supply circuit, an electriccurrent load Gil"- cuit, and electric valve means interconnecting saidcircuits comprising an anode and a cathode constituting spacedelectrodes for the flow of current thereloetween, of means forcontrolling flow of current co a control electrode c ns ut means, andmeans for producing and impressing i on said control electrode potentialimpulses of substantially perpendicular wave front comprisa controlcircuit having included therein a reactor and an auxiliary electricvalve con nected to receive an electromotive similar to theelcctromotive of said supply circuit. discharge controlling means forsaid auxiliary valve, energi ng means operating in relation to the volt-.age cycle said supply circuit for controlling the action. of saiddischarge controlling means, and means coupling said reactor with saidcon- .trol electrode to impress on the latter a poten- 3. In a system ofthe character described, the combination with a load circuit, of meansfor producing and impressing on said circuit potential impulses ofsubstantially perpendicular wave front comprising a source ofalternating current, a reactonnieans comprising an electric valve havingan anode and a cathode connecting said source with said reactor andconstituting spaced electrodes for the flow or current'of. unidirectiononly through said reactor, means for rendering said valve conductive andnon-conductive at recurring intervals in relation with the voltage cycleof said source of current,'and means connecting said load circuit acrosssaid reactor.

4. In a system of the character described, the combination with a loadcircuit, of means for producing and impressing on said circuit potentialimpulses of substantially perpendicular wave front comprising a sourceof alternating current, a reactor, means comprising an electric valvehaving an anode and a cathode connecting said source with saiu reactorand constituting spaced electrodes for the fiow of current ofunidirection only tlirous aid reactor, means for rendering said valve.onductive and non-conductive for saidflow of: c rrent at recurringintervals in relation with the voltage cycle of said source of current,and means comprisinga transformer inductively connecting said loadcircuit across said reactor.

5. In a system of character described, the combination with a loadcircuit, of means for producing and impressing on said circuit potentialimpulses of substantially perpendicular wave front comprising a reactor,means comp-rising a plurality of electric valves each comprising ananode and a cathode connecting said source with said reactor andconstituting spaced electrodes for the flow of current of unidirectiononly through said reactor, means comprising a plurality of controlelectrodes severally associated with aid anodes and a source of controlpotential for sequentially rendering said valve conductive andnon-conductive for said'fiow of current at recurring intervals withrespect to the voltage of said source of current, and means forconnecting said load circuit across saidreactor.

6. In a systemfor contr lling the'ilow of electric current. electriccurrent su y line, else-- trio translation means connected. with saidline and comprising. an alternating current winding and an electricvalvehaving an anode. control electrode and a cathode. an electric cu tout-- put line connected with said translation means, a circuitconnected to rec ve an electromotive force similar to electro iotiveforce of said Winding, including a reactor Xiliary electric valve havingu.-

control end said valve to alternat y cmdr'ct and non-conductive recurrlg: intervals in relation with the voltage cycle of said wh ling.

transformer c nnected to impress between the first saidcontrol'electrode and cathode potential. component similar to a comonent of the potential between the second s i anode and cathode.

'7. In a system i trio current, an el trio trs ation and com rising anand an electric vain electrode and a cath controlling the flow of elem Al- 7 line "l alter ating rent 1 incline; having anode, control o anelectric current out- 15. drop in said reactor.

8. In a system for controlling the flow of elec- ,tric current, anelectric current supply line, lectric translation means connected withsaid line and comprising an alternating current windiilingand anelectric valve having an anode, a control electrode and a cathode, andan electric current output line connected with said translation means; acircuit connected to receive an electroinotive force similar to anel-ectromotive rforce of said winding, and including a reactor and apair of auxiliary electric valves operatively connected to supplyuni-directional current to said reactor, each valve having an anode, acontrol electrode, and a cathode; means for impressing on the secondsaid control electrodes recurring potentials of signs and magnitudesoperative to cause each of the second said valves to be alternatelyconductive and non-conductive in sequence with respect to the othervalve in rela- 85 tion with thevoltage cycle of said source, and

means for impressing between the first said control electrode andcathode a potential component similar to a component of the potentialdrop in said reactor. 1

9; In a system for controlling the fio'w of elec- "tric current, anelectric current supply circuit,

electric translation means connected with said circuit and comprising analternating current winding and anelectric valve having an anode, acontrol electrode and a cathode; an electric current output circuitconnected with said translation neans, means including an auxiliaryelectric valve for impressing on said control electrode recurringpotentials of signs and magnigudes operative to control the flow ofcurrent means for converting the last saidpotential into uni-directionalcontrol potential.

10. In a system for controlling the flow of electric current, anelectric current supply circuit, electric translation means connectedwith said circuit and comprising an alternating current winding andan'electricvalve having ananode, a control electrode and a cathode; anelectric current output circuit connected with said translation means,means including an auxiliary electric valve for impressing on saidcontrol. electrode recurring potentials, of signs and magnitudesoperative to control the flow of current through'the first said valve,said auxiliary valve having an anode, a control electrode and a cathode,means for impressing control potentials on the second's'aid controlelectrode and including means for obtaining an alternating potential in75: relation with the intensity of the flow of current hrcugh the firstsaid valve, said auxiliary valve,

through said translation means, non-linearly resonant impedance .l canscontrolling the relation between the last said potentialtandtheintensity of said flow ofcurrent, a d means for converting the last saidpotential into uni-directional control potential; j

11. In a system for controlling the flow of electric current, anelectric cu supply circuit, electric translation means connected withsaid circuit and comprising an alternating current winding and anelectric valve having; an anode, a control electrode and a cathode, anelectric current output circuitconnected with said translation means;means including anauxiliary electric valve for impressing on saidcontrol electrode recurring potentials of signs and magnitudes operativeto central the flow of current through the first said valve, auxiliaryvalve having an anode, a control electrodeand a cathode; and'meansfor-impressing control potentials on the second said control electrodeand including means for obtaining a-uni-directional potential inrelation with the magnitude of the flow'or energy between said circuits.V

12. In a system for controlling the how of electric current, an electriccurrent supply circuit, electric translation means connected with saidcircuit and comprising an alternating current cathode; means foriinpressing'control potenponent of the flow of current in saidalternating current circuit; and means for converting the last saidpotential into uni-directional control potential.

13. In a system for controlling the flow of electric current, anelectric current supply circuit,

electric translation means connected with said circuit and comprising anal hating current winding and an electric valve having an anode,

a control electrode and a cathode; anelectrio current output circuitconnected with said translation means, one of said circuits being analternating current circuit, means including an auxiliary electric valvefor impressing on said control electrode recurring potentials of signsand magnitudes operative to control. the flow of current through thefirst saidrvalv'e, said auxiliary valve having an anode, a controlelectrode and a cathode; and for impressing control potentials on thesecond said central electrode and including means for obtaining,auni-directional control potential in relation with the power factor ofthe how of current in said alternating current circuit.

14. In a system for controlling the flow of electric current, anelectric. current-supply cir-' cult, electric translation meansconnected with said circuit and comprising analternating current windingand an electric valve having an anode, a control electrode and acathode; an electric current output circuit connected with saidtranslation means, means including an auxiliary electric valve havingconnections with the said control electrode for recurringly impressingthereon potentials of signs :and magnitudes operative to'controltheflow, of current; through the firstsaid valve, said auxiliarylyalvehaving an anode, a, control .electrode and a cathode; means forimpressing -controlpotentials on' the second, said control electrode,and meansuresponsive to abnormal conditions within'the system formodiiyingthe said connections 10f the sec-: ond said valve to constantlyimpress a negative potential on the first saidicontrol electrode.

15. In a system for controlling the flow of electric current, anelectric current supply circuit, electric translation means connectedwith said circuit and comprising an alternating current winding and anelectric valve having an anode, a control electrode and a cathode; anelectric current output circuit connected with said translation means,means including an auxiliary electric valve for impressing on saidcontrol electrode recurring potentials of signs and magnitudes operativeto control the flow of current through the first said valve, saidauxiliary valve having an anode, a control electrode and,

a cathode; means for impressing control potentials on the second saidcontrol electrode, means for obtaining an alternating potential inrelation with the intensity of the flow of current through saidtranslation means, non-linearly resonant impedance means controlling therelation between the last said potential and the intensity of said flowof current, means for converting the last said potential intouni-directional control potential, and means for impressing saiduni-directional potential on the first said control electrode.

16. In a system for controlling the flow of electric current, anelectric current supply circuit, electric translation means connectedwith said circuit and comprising an alternating current Winding and anelectric valve having a plurality of anodes with associated controlelectrodes and a cathode; a load device connected with the first saidwinding and with said valve, means including auxiliary electric valves,for impressing on said control electrodes recurring potentials of signsand magnitudes operative to control the flow of current through thefirst said valve, each said auxiliary valve having an anode, a controlelectrode and a cathode; and means for impressing control potentials oneach second said control electrode including means operable to producean alternating potential variable in magnitude in dependence upon theintensity of the flow of current through said translation means andincluding means for converting the last said potential intouni-directional control potential.

17. In a system for controlling the flow of electric current, thecombination with an electricv current supply circuit, an electriccurrent load circuit, and electric valve means comprising an anode and acathode interconnecting said circuits and constituting spaced electrodesfor the flow of current therebetween, of means for controlling said flowof current comprising an element of said valve means, means comprisingan auxiliary electric valve coupled with said element for recurringlyimpressing thereon potential of such sign and magnitude and during suchmoments as to control the moments of initiation of said flow of current,means for controlling the said moments of the impression of saidpotential on said element comprising an element of said auxiliaryelectric valve, means for impressing potential on the last said elementof such sign and magnitude and during such moments as to render-the saidauxiliary valve recurringly conductivei: and imeansv responsive to anabnormal condition of said system for rendering the said auxiliary valveconstantly non-conductive.

' ;18. In a system for controlling the; flow of electric. current; thecombination with .anzelectric current,- supply circuit, an electriccurrent load; circuit; and ,electric valve means comprising :ananodeandafcathode interconnecting. said circuits and constituting spacedelectrodes for the flow of current therebetween, of means forcontrolling said flow of current comprising an element of said valvemeans, means comprising an auxiliary electric valve coupled with saidelement for recurringly impressing thereon potential of such sign andmagnitude and during such moments as to control the moments ofinitiation of said flow of current, means for controlling said momentsof impression of said potential on said element comprising an element ofsaid auxiliary electric valve, means for impressing potential on thelast said element of such sign and magnitude and during such moments asto render said auxiliary valve recurringly conductive,-means operableresponsive to an operating condition of said system for varying themoments of impression of said potential on the last said element, andmeans responsive to an abnormal condition or said system for impressingpotential on the last said element of such sign and magnitude as torender the said auxiliary electric valve constantly non-conductive.

19. The combination with an alternating current supply circuit, anelectric current work circuit, and electric valve means interconnectingsaid circuits comprising an anode and a cathode constituting spacedelectrodes for the flow of current therebetween, of means forcontrolling said flow of current comprising a control electrodeconstituting an element of said valve means, means i'or producingpotential impulses of substantially perpendicular wave front comprisinga control circuit having included therein a resistor serially connectedwith an inductive reactor and an auxiliary electric valve, dischargecontrolling means connected for cyclically controlling the initiation ofsaid potential impulses, and means coupling said control circuit withsaid control electrode to impress on the latter a potential componentsimilar to a component of the potential across a portion only of saidcontrol circuit.

20. The combination with an alternating current supply circuit, anelectric current load circuit, and electric valve means interconnectingsaid circuits and comprising an anode and a cathode constituting spacedelectrodes for the flow of current therebetween, of means forcontrolling said flow of current comprising an element of said valvemeans other than said electrodes, means for impressing on said element apotential comprising an alternating voltage component and aunidirectional voltage component, and means operable in dependence uponvariations in the said flow of current for varying the magnitudes ofsaid components.

, 21. In an electric current converting system, the combination with anelectric current supply circuit, an electric current load circuit, andelectric valve means interconnecting said circuits and comprising ananode and a cathode constituting spaced electrodes for the flow ofcurrent therebetween, of means for controlling said ilow of currentcomprising an element of said valve means, means comprising an auxiliaryelectric valve coupled with said element for impressing thereonpotential of such magnitude and during suchmomentsas to control themomentsfiof initiation of said flow of current, means for controllingsaid moments of the impression of said potential on said elementcomprising an elementof said auxiliary electric valve, means forimpressing onsaid'element of said'auxiliary valve a potentialvcomprising superimposed alternating 10 and unidirectional components ofsign and mag nitude and during "suchm'oments as to 'render the'saidauxiliary valve recurringly conductive, means operablein'dependence upona predetermined electrical condition of said system forproducing-saidunidirectional component, and

meansoperable'in dependence upon another predetermined. electricalcondition of said system forvcontrolling the operation of the said meansfor producing said unidirectional component.

ISADORE :K. -DOR'I1ORT. 10

